Automatic circuit-breaker.



l N. H. HOLLAND. AUTOMATIG CIRCUIT BREAKER. I APPLICATION FILED OUT. 22,1904. RENEWED MAR. 18, 1909.

937,242, Patented Oct-19,1909.

g l s': I Eigenfaf: w/[adw UNITED srnrns PATENT oFFIon E. HOLLAND, OFBROOKLINE, MASSACHITSETTS, ASSIGNOR 'I O WESTERN ELECTRIC COMPANY, OFCHICAGO, ILLINOIS, ACORPOR'ATION OF ILLINOIS,

AUTOMATIC CIRCUIT-BREAKER.

Specification of Letters Patent.

Application filed October 22, 1904, Serial No. 229,640. Renewed Illarch18, 1909. Serial No. 484,275.

To all whom it may concern:

Be it known that I, NEWMAN H. HonnANo, a citizen of the United States,residsex and State of Massachusetts, have invented an Improvement. inAutomatic Circuit-Breakers, of which the following description, inconnection with the accompanying drawings, is a specification, likeletters on the drawings representing like parts.

The presentinventim relates to an automatic circuit breaker, the purposeof which is to cause an electric circuit to be automatically opened incase an excessive current passes over the line, so as to prevent theburning out of the working circuits, electro nyignets, &c., in thesystem.

i In accordance with the invention, the circuit is provided withterminals which are under a tension, as that of a weight or spring,normally tending to separate them and break the circuit, these terminalsbeing connected together when inuse by an intermediate conductor of suchcapacity as to become heatedwhen an abnormal current passes over theline. ThlS conductor is arranged in proximity to a device which servesas a frictional holding member to maintain the two terminals inelectrical engagement with the conductor. so as to complete the circuit,this frictional holding device being so arranged with relation to theconductor as to be heated and expanded thereby if an abnormal current isflowing, the expansion serving tocause the release of the terminalfriction-ally engaged withsaid member, thus permitting the two terminalsto separate and break the circuit. tionally engaged may have difi'erentcoefii- 'cients of expansion, or may be arranged so that the heatingaction of the current may be imparted to one, without beingsubstantially imparted to the other, or both of these characteristicsmay be. and preferably are, taken advantage of. v

By this invention a simple and etlicient protective device forelectrical circuits, commonly known as a vided. 4

It is also evident that this invention contemplates the holding togetherby frictional engagement of any two opposing members under thevstresstending to separate them, thefrictidnal engagement being overcomebysuch. application of heat. to. the parts aszto,

heat coil may be prolng in Brookline. in the county of Middle- The twomembers which are fricin the position shown in Fig: 1, by means ofaprojection a connected with the terminal a, and fitting closely in anintermediate member c which, in turn, connected with the member I). Inaccordance with the inven- Patenteaoct. 1e, 190a. I

tion, this intermediate member 0 is arranged I to be directly influencedby the heat of an excessive current flowing over the circuit, and,preferably, is of a material having a higher coefilcient of expansionthan that of the projection or pino so that it will expand with relationto the said pin when heated, thus relieving the frictional hold upon thepin and permitting the terminals a and b to spring apart. I i

As herein shown, thememberc consists of a spool of insulating materialsuch, for ex.- ample, as hard rubber, having a longitudinal bore 0 inwhichthe projection or pin a fits tightly, the saidsspool in turn beingconnected with. the conductor 1) so that, when the pin a connected withthe conductor a is pushed into the. socket 6-, the parts will be,-

, by a spring member'or clip I) connected with,

the member I) and thereby establishing electrical contact between thesaid member I) andthe coil c r-The other endof said coil 0 is connectedwith a disk a supported upon the opposite end of the spool and in electricalvcontact with a spring member awhich is connected with the membera so as to close thecircuit between thetwo terminals so long as themembers anndb. are prevented fromspringing apart; The two members arenormally held together Wholly by the frictional fit of the pin a in thebore in the spool, and as soon as an abnormal current comes on the linecausing the said spool 0 to become -5 heated, and to expand, the pin awill be re leased, and the two members will fly apart breaking thecircuit and protecting the instruments which might otherwise be burnedout.

As is apparent, after operation the protective device may be placed incondition for further use merely by returning the pin a to the opening0" as soon as the spool c has sufficiently cooled ofi to frictionallyengage said pin.

It is not intended to limit the invention to the specific constructionand arrangement shown and described, since modifications may be madewithout departing from tlie said invention.

What I claim is:

1. The combination with two frictidnally engaging members, of meanstending to cause relative movement of the same, and means for applyingheat to said members to cause unequal expansion thereof; whereby thefrictional engagement of said members is overcome and their relativemovement effected.

2. A protector for electrical circuits comprising a heat coil having anopening therein and a pin frictionally secured in said opening; wherebyan abnormal currentin the circuit expands said heat coil and permits arelative movement of said heat coil and pin, thereby opening thecircuit.- 3. In a protector for an electric circuit, the combinationwith.a spool having an opening therein, of a heat producing coil woundon said spool, said forming part 4 0 of said electric circuit, apirrex'tending from said opening and frictionally secured therein, saidfrictional engagement of the pin being adapted to be overcome byexpansion of i said spool due to an abnormal current in said coil.

f 4. In a protector for an electric circuit, the combination with aterminal provided with a spool, ofa heat producing coil for ,said spool,said coil forming part of said clectric circuit, a second terminalprovided "with means for frictionally engaging said spool; whereby anabnormal current in the circuit produces an expansion of said spool andovercomes thef'rictional engagement of the parts, thereby opening thecircuit.

5; In an automatic circuit breaker, a pair of terminals; means tendingto separate said terminals to break the circuit; a conductor in thecircuit; a device carried by one terminal and adapted to be heated byheat de- 'veloped in said conductor due to an abnormal current; and adevice carried by the other terminal frictionally held by said firstnamed device and released by the expansion 55 thereof.

teases 6 Tn an automatic circuit breaker, a pair of terminals springpressed away from each other; an intermediate member connected with oneof said terminals and provided with an opening adapted to receive andfric- I release the frictionally heldprojection, and

permit the separation of the spring terminals, substantially asdescribed.

7. The combination with spring terminals; of a spool or core providedwith a winding, the ends of which are adapted to be con nected with saidterminals, respectively; means for detachably securing the said spool toone ofsaid terminals; and a frictional engaging member afiording meansfor attaching said spool to the other of said terminals, said memberbeing adapted to be released by the expansion of the spool due to anabnormal current, substantially as described.

8. In apparatus of the class specified, the combination of a device,expansible by heat, means for generating heat to expand said device, onthe passage of an-unduly strong current, means for frictionally engagingsaid device when unexpanded, the device being adapted to become relievedof its frictional engagement on expanding, and circuit controlling meansnormally tending to operate but held in restraint by the frictionalengagement of said device and released by the expansion andlisengagement of said device, substantially as described.

9. In apparatus of the class specified, the combination of a deviceexpansible by heat, means for generating heat to expand said device onthe passage of an unduly strong current, means for frictionally engagingsaid device when llITXPlIlClGCl, the device being adapted to becomerelieved of its frictional engagementon expanding, and circuit openingmeans normally held in restraint by said device but released when saiddevice is expanded and relieved of its frictional engagement,substantially as described.

10. The combination of an expansible sleeve, an inclosure within thesleeve normally making frictional engagement with the sleeve, a heatconcentrating device associated with the sleeve, and circuit controllingmeans governed by said sleeve, substantially as described.

11. The combination of a pair of frictional elements adapted to normallycngage each other frictionally, said elements having differentcoetlicients of expansion, and means for varying the temperature inaccordance with variations in the circuit conllt ' sage of an undulystrong current;

seams ditions to cause frictional engagement and disengagement of saidelements with one another, substantially as described;

12. An electrical circuit controller, comprising thermally operablemeans for controlling the circuit, and having a frictionallysecured'slidable member releasable. to control the "circuit, on a changein'circuit conditions.- i p .13. An electrical circuit controller,comprising thermally operable means for controlling the circuit, andhaving a slidable "member releasable by expansion to control thecircuit.

14. An electrical circuit protector, com

16 An electrical circuit protector, cornprislng a plug, an ex anslbleand COIItIaCtIf ble collar arranged t ereon, a he'ating'de. ,vicefor-expanding said collar on-the passage-of an unduly strong current,and cir- (suit-controlling devices operable on the movement of saidcollar.

17. An electrical circuit protector, com

prising a plug, an expansible and contract-ible collar arranged thereon,a'heat coil car- 35 ried by said collar, the collar being frictionallyenga'geable upon the plug, spring means for actuating the collar whenreleased, and circuit-controlling devices operable by the movement ofthe collar.

18. An electrical circuit protector, comprising a plug, an expansiblecollar arranged thereon, a heat coil carried by" said, collar;

the collar being frictionally engageab'le' upon the plug and releasableon expansion by the passage of'an unduly strong current through. saidheatcoil, spr ng means tend-- ing to slide the-collar along the plug,and

contacts arrapg ,,.se openthe circuit on the actuation of thecollar.

In testimony whereof, I have signed my name to thisspecification'in thepresence of two subscribing Witnesses.

NEWMAN HFHOLLANP. -Witnes ses: r I

HENRY J. LIvER onE, VMARGARET E. COVENEY.

